Generator GUI textures

[Glassmaker]

Need GUI textures for Generators, all generators have have power bar to the left for buffer storage indicator.

• Coal would have a burning slot and flame under it, like the furnace.
• Flowstone would have another bar to the right for fluid storage (Check the liqifier GUI), and a slot in the middle for input slot.
• Lava would be same as like the flowstone one.
• Solar would have Sun display for the current position of the sun.